Liquid cooling device for power battery pack

The invention provides a liquid cooling device for a power battery pack. The liquid cooling device comprises a liquid cooling pipeline which is stored in the battery pack and is used for enabling cooling liquid to flow through; the liquid cooling pipeline is snake-shaped and comprises N heat absorption pipes which are arranged in parallel and are uniformly arranged at intervals, and (N-1) connecting pipes which are used for connecting and communicating each two adjacent heat absorption pipes, wherein N is a positive integer which is not less than 2; each heat absorption pipe is of a retracting-expanding structure and comprises a plurality of retracting-expanding units which are connected in sequence; each retracting-expanding unit comprises an expanding section and a retracting section; the expanding section of each retracting-expanding unit is connected with the retracting section of the adjacent retracting-expanding unit; two ends of each connecting pipe are connected with two end parts located at the same